Great American Eclipse: Everything you need to know to get ready

时间：2017-08-25 05:00:03166网络整理admin

Henry Groskinsky/Getty By Leah Crane On 21 August, the continental US will see its first total solar eclipse since 1979. The moon will pass between Earth and the sun at just the right time and in just the right place to cast a shadow that will sweep across the nation. In preparation, New Scientist is here with everything you need to know about the Great American Eclipse. Where do I need to be to see the eclipse? To see the moon completely block out the sun, you’ll need to be within the 110-kilometre-wide strip that the moon’s shadow will cut across the US, beginning in Oregon and travelling eastwards through to South Carolina. Even in those areas, totality – the total blocking of the sun – will only be visible for 2 to 3 minutes before the moon moves on. If you’re not within the path of totality, you can still see a partial eclipse. The entire US, Canada and Central America will be able to see the moon seem to take a bite out of the sun. Even north-western Europe will get a glimpse in the late afternoon. What equipment do I need? Whether you’re in the path of totality or not, you’ll need eclipse glasses. The moon will block out at least part of the sun, but looking directly at it could still permanently damage your eyes. Even the darkest of sunglasses let through thousands of times more sunlight than your eyeballs can handle. Eclipse glasses are fitted with a solar filter that blocks out enough light for you to safely look at the sun. They are available at many public libraries and scientific institutions across the country, but make sure yours are ISO certified. If you can’t get eclipse glasses before 21 August, don’t risk looking directly at the sun. Instead, you can use a method called pinhole projection: by letting sunlight shine through an opening, such as a hole in a sheet of paper, and onto another surface, you can see a projection of the crescent sun. You don’t even need a sheet of paper: this will also happen with sunlight passing through the leaves of a tree, or you can just let the sun shine through your fingers onto the ground. Just don’t look through the paper or your fingers. Will science be happening during the eclipse? How can I help? Yes, solar physicists will be learning about the sun’s corona, which is so dim that we can only see it by eye when the rest of the sun is blocked out. Other researchers will study everything from how a brief moment of shadow affects Earth’s atmosphere, to the sudden temperature drop that comes with an eclipse, to how plants and animals act weirdly during it. There are lots of citizen science projects that will let you help researchers gather data about all these things just using a camera or phone app. Visit NASA’s citizen science website to learn more. Should I be worried about the eclipse? Not unless you look directly at the sun without protection. There will be no freak earthquakes or animal uprisings or apocalyptic horsemen during the eclipse. At least, none that wouldn’t have happened anyway, regardless of the moon’s position. I won’t be able to view the eclipse at all. Are there any more in the next decade? The next two total solar eclipses will be in July 2019 and December 2020. They’ll both be visible from areas around Argentina and Chile. In 2021, a total eclipse will pass across Antarctica. In 2024, another one will pass through Mexico, the central US and parts of Canada. There will be total eclipses in 2026, 2027 and 2030. So if you’re willing to travel, you can still see six solar eclipses in the next 10 years, even if you miss this one. More on these topics: